Batterieshave two sides: positive and negative. Thisis no problem with me, but other people in my country call them'plus' and 'minus'. I though this is wrong usage, however, a on-linedictionary says 'positive pole' can be called as 'plus pole'. Isthis true?
I think when people say 'plus' and 'minus', talking about batteries, they are not really thinking about the science behind how batteries work. They are just talking about the symbols on the batteries themselves. For that reason, 'plus pole' sounds odd to me. I've never heard it anyway. But I have definitely heard people talking about the 'plus end' or 'plus side' of the battery.
In everyday conversations about batteries I think people often use the word "terminal" rather than "pole".
eg When inserting a new battery, make sure that the positive terminal (+) faces the + symbol printed on the battery compartment.
Cell batteries, such as those used in watches do indeed have a positive and a negative side.
Some batteries (marked AA, AAA, etc. in the USA and UK) are long and thin, in which case I tend to talk about the positive or negative end.